KR950000632B1 - Continuous process for producing 5-vinyl-2-norbornene - Google Patents

Abstract

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Description

Continuous production method of 5-vinyl-2-norbornene

The present invention relates to cyclopentadiene and butadiene or cyclopentadiene and dicyclo in the presence of N, N-diethylhydroxylamine or 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl 5-vinyl-2-norbornene characterized by continuously introducing a mixture of pentadiene and butadiene into a pressure resistant reactor, reacting in the absence of a gas phase portion within the pressure resistant reactor and continuously withdrawing the reaction product It relates to a continuous manufacturing method of. 5-Vinyl-2-norbornene is very useful as a raw material of 5-ethylidene-2-norbornene used as the third termonomer of EPDM.

The Diels-Alder reaction is characterized by the addition of olefins with double bonds (dienofils) activated by conjugated dienes. Since the reaction proceeds thermally, it is preferable to carry out the reaction at a relatively high temperature, for example, 70 to 250 ° C. However, at such high temperature reactions, cyclopentadiene and butadiene in the raw material and cycloolefin in the reaction product are easily polymerized, which leads to the closing of the reactor by deposition and adhesion of the polymer and the formation of a film of polymer on the inner wall surface of the device. It causes a problem such as that, and makes it difficult to carry out continuous operation substantially for a long time.

As a method of preventing the polymerization of the reactants in the Diels-Alder reaction conducted at a relatively high temperature, for example, British Patent No. 923,462 describes the addition of an organic cobalt compound, and US Patent No. 3,201,484 describes an organic nickel compound. The addition of is described. However, these compounds are unsuitable for use in conducting Diels-Alder reactions because they are unstable in air and difficult to handle. In addition, Japanese Patent Application Publication No. 7,131 / 82 describes the use of D-phenylene diamine or the like as a polymerization inhibitor, but its effect is not satisfactory.

Another problem involved in the Diels-Alder reaction is that all of the reactants are dienes and act as dienophils, resulting in various reaction products during the reaction. Thus, in addition to the desired 5-vinyl-2-norbornene and the above-described polymers, 4-vinyl-1-cyclohexene, tetrahydroindene, cyclooctadiene and the like are produced, and in particular, 5-vinyl-2-norne A significant amount of 4-vinyl-1-cyclohexene (dimer of butadiene) is produced which causes a decrease in the selectivity of bornen.

It is an object of the present invention to solve the above-mentioned drawbacks, that is, in the method of producing 5-vinyl-2-norbornene by the aforementioned Diels-Alder reaction, the closure of the reaction apparatus by precipitation and deposition of polymers. And it provides a method for long-term continuous production of 5-vinyl-2-norbornene with excellent selectivity by preventing problems such as the formation of a polymer film on the surface of the inner wall of the device.

The present invention relates to 10-10,000 ppm N, N-dihexylhydroxylamine or 4-oxo-2, based on the total weight of cyclopentadiene and dicyclopentadiene or the total weight of a mixture of cyclopentadiene and dicyclopentadiene and butadiene. 2,6,6-tetramethylpiperidine-1-oxyl is added, and the resulting reaction mixture is continuously introduced into the pressure resistant reactor, reacted in the absence of gas phase in the pressure resistant reactor, and the reaction product is continuously taken out. The present invention relates to a method for continuously producing 5-vinyl-2-norbornene from cyclopentadiene and butadiene or a mixture of cyclopentadiene and dicyclopentadiene and butadiene by Diels-Alder reaction.

The byproduct 4-vinyl-1-cyclohexene is produced by the dimerization reaction of butadiene. According to the analysis of the present inventors, if a gaseous portion is present in the pressure resistant reactor, a relative concentration of butadiene having a high vapor pressure when cyclopentadiene or a mixture of cyclopentadiene and dicyclopentadiene reacts with butadiene is obtained in the gas phase portion in the pressure resistant reactor. It becomes high and promotes formation of 4-vinyl-1-cyclohexene.

According to the process of the present invention, cyclopentadiene or a mixture of cyclopentadiene and dicyclopentadiene is continuously introduced into a pressure resistant reactor, the reactor is filled with liquid and reacted under conditions such that it contains no gaseous portion at all and the reaction product Withdrawal continuously can reduce the formation of 4-vinyl-1-cyclohexene and increase the selectivity of 5-vinyl-2-norbornene over butadiene.

In addition, polymerization in the pressure resistant reactor is suppressed by continuously injecting N, N-diethylhydroxylamine or 4-oxo-2,2,6,6-tetramethylpiperidine-1oxyl as a polymerization inhibitor into the pressure resistant reactor. Continuous operation can be continued for a long time without problems such as closing of the device by deposition and adhesion of the polymer and formation of a polymer film on the inner wall surface of the device. In addition, since the polymerization of butadiene and 5-vinyl-2-norbornene is inhibited, the selectivity of 5-vinyl-2-norbornene to butadiene can be increased.

The method of the present invention is about 80 ~ 180 ℃, preferably at a temperature of 90 ~ 160 ℃, and about 5 ~ 60㎏ / ㎝ ^2, preferably metered into the reactor pressure was maintained at a pressure of 10 ~ 45㎏ / ㎝ ² A pump is used to inject cyclopentadiene and butadiene or a mixture of cyclopentadiene and dicyclopentadiene and butadiene, and about 10 to 10,000 ppm, preferably 100 to 5,000 ppm N, based on the total weight of the feedstock, N-diethylhydroxylamine or 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl is continuously added and reacted for about 0.1 to 5 hours, preferably about 0.3 to 2 hours. The reaction product is taken out continuously while simultaneously.

The invention is explained in more detail in the following examples. In the examples, the amount of polymerization byproducts was determined quantitatively by treating the reaction solution at 92 ° C. under reduced pressure of 2 mmHg and measuring the amount of heavy material remaining.

Example 1

The residence time was set to 35 minutes by supplying 1.2: 1 molar ratio of butadiene and cyclopentadiene using a plunger pump in a pressure resistant reactor at a temperature of 140 ° C. and a pressure of 40 kg / cm ² . . At the same time, 2,500 ppm of N, N-diethylhydroxylamine was added as a polymerization inhibitor. The reaction solution was continuously taken out and analyzed while maintaining the reactor filled with liquid. The reaction was carried out continuously for 1,000 hours. After the reaction was completed, no precipitation of polymerization byproducts was observed in the autoclave and the inside of the reactor was clean. The concentration of polymerization byproduct in the reaction solution was 0.04% by weight.

The reaction results by gas chromatography analysis were as follows: conversion of butadiene: 21.0%; Selectivity of 5-vinyl-2-norbornene with respect to butadiene: 67.8%; Selectivity of 4-vinyl-1-cyclohexene relative to butadiene: 16.8%.

Example 2

200 ml held at a temperature of 130 ° C. and a pressure of 35 kg / cm ² were supplied with 1.3: 1.0 molar ratio of butadiene and cyclopentadiene by using a plunger pump in a pressure resistant reactor to obtain a residence time of 50 minutes. . At the same time, 1,500 ppm of N, N-diethylhydroxylamine was added as a polymerization inhibitor. The reaction solution was continuously carried out while maintaining the reactor filled with liquid. After completion of the reaction, no precipitation of polymerization byproducts was observed in the autoclave and the inside of the reactor was clean.

The concentration of polymerization byproducts in the reactor was 0.03% by weight.

The reaction results by gas chromatography analysis were as follows: conversion of butadiene: 16.7%; Selectivity of 5-vinyl-2-norbornene with respect to butadiene: 70.1%; Selectivity of 4-vinyl-1-cyclohexene to butadiene: 16.6%.

Example 3

The reaction was carried out under the same conditions as in Example 1 except that 600 ppm of N, N-diethylhydroxylamine was added instead of 2,500 ppm of N, N-diethylhydroxylamine. The reaction was carried out continuously for 500 hours. After completion of the reaction, no precipitation of polymerization byproducts was observed in the autoclave and the inside of the reactor was clean. The concentration of polymerization byproduct in the reaction solution was 0.17% by weight.

The reaction results by gas chromatography analysis were as follows: conversion of butadiene: 21.3%; Selectivity of 5-vinyl-2-norbornene with respect to butadiene: 67.0%; Selectivity of 4-vinyl-1-cyclohexene to butadiene: 16.6%.

Example 4

The residence time was set to 35 minutes by supplying 1.2: 1 molar ratio of butadiene and cyclopentadiene using a plunger pump in a pressure resistant reactor at a temperature of 140 ° C. and a pressure of 40 kg / cm ² . . At the same time, 2,500 ppm 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl was added as a polymerization inhibitor. The reaction solution was taken out and analyzed continuously while keeping the reactor full of liquid. The reaction was carried out continuously for 120 hours. After the reaction was completed, no precipitation of polymerization byproducts was observed in the autoclave and the inside of the reactor was clean.

The concentration of polymerization byproducts in the reactor was 0.16% by weight.

The reaction results by gas chromatography analysis were as follows: conversion of butadiene: 21.3%; Selectivity of 5-vinyl-2-norbornene with respect to butadiene: 67.1%; Selectivity of 4-vinyl-1-cyclohexene to butadiene: 16.6%.

Example 5

A mixture of butadiene and 95% by weight of cyclopentadiene and 5% by weight of dicyclopentadiene was prepared using a plunger pump in a 200 ml reactor equipped with a temperature of 130 ° C. and a pressure of 35 kg / cm ² . The molar ratio of butadiene to cyclopentadiene was supplied to be 1.3: 1.0 so that the residence time was 50 minutes. At the same time, 1,500 ppm of 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl was added as a polymerization inhibitor. The reaction solution was taken out and analyzed continuously while keeping the reactor full of liquid. The reaction was carried out continuously for 140 hours. After the reaction was completed, no precipitation of polymerization byproducts was observed in the autoclave and the inside of the reactor was clean.

The concentration of polymerization byproducts in the reactor was 0.11% by weight.

The reaction results by gas chromatography analysis were as follows: conversion of butadiene: 16.9%; Selectivity of 5-vinyl-2-norbornene over butadiene: 69.6%; Selectivity of 4-vinyl-1-cyclohexene relative to butadiene: 16.5%.

Example 6

The reaction was carried out under the same conditions as in Example 1 except that 600 ppm of 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl was added instead of N, N-diethylhydroxylamine. . The reaction was carried out continuously for 120 hours. After completion of the reaction, no precipitation of polymerization byproducts was observed in the autoclave and the inside of the reactor was clean.

The concentration of polymerization byproducts in the reaction solution was 0.6% by weight.

The reaction results by gas chromatography analysis were as follows: conversion of butadiene: 22.2%; Selectivity of 5-vinyl-2-norbornene with respect to butadiene: 64.4%; Selectivity of 4-vinyl-1-1-cyclohexene to butadiene: 16.0%.

Comparative Example 1

27 g of cyclopentadiene, 27 g of butadiene and 0.2 g of N, N-diphenyl-p-phenylenediamine were added and reacted at 140 ° C. in a 200 ml reactor. The reaction time was chosen to obtain the same conversion (%) as in Example 1.

After the reaction was completed, it was observed that the polymerization reactant precipitated in the autoclave and the inside of the reactor was contaminated. The reaction results by gas chromatography analysis were as follows: conversion of butadiene: 24%; Selectivity of 5-vinyl-2-norbornene with respect to butadiene: 43%; Selectivity of 4-vinyl-1-cyclohexene to butadiene: 41%.

Comparative Example 2

A continuous operation was performed under the same conditions as in Example 1 except that no polymerization inhibitor was added. After completion of the reaction it was observed that the autoclave was full of polymerization byproducts and contaminated inside. The concentration of the polymerization byproduct in the reaction solution was 2.5% by weight. The reaction results by gas chromatography analysis were as follows: conversion of butadiene: 25%; Selectivity of 5-vinyl-2-norbornene relative to butadiene: 54%; Selectivity of 4-vinyl-1-cyclohexene to butadiene: 17%.

In the process for preparing 5-vinyl-2-norbornene from cyclopentadiene and butadiene or from cyclopentadiene and dicyclopentadiene and butadiene by Diels-Alder reaction, the total weight of cyclopentadiene and butadiene or cyclopentaene 10 to 10,000 ppm N, N-diethylhydroxylamine or 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl relative to the total weight of the diene and the mixture of dicyclopentadiene and butadiene Is added, and the resulting mixture is continuously injected into the pressure resistant reactor, reacted in the pressure resistant reactor in the absence of gas phase and continuously withdrawn the reaction product, thereby closing the inside of the device by precipitation and adhesion of the polymer and forming a polymer film on the inner wall of the device. The reaction can be carried out with a good selectivity for a long time without problems such as being.

Claims (4)

10-10,000 ppm of N, N-diethylhydroxylamine is added to the total weight of cyclopentadiene and butadiene or the total weight of the mixture of cyclopentadiene and dicyclopentadiene and butadiene, and the resulting mixture is continuously Of cyclopentadiene and dicyclopentadiene and butadiene by means of a Diels-Alder reaction, characterized in that it is introduced, reacted in the absence of a gas phase portion in a pressure resistant reactor and the reaction product is taken out continuously. Process for continuously preparing 5-vinyl-2-norbornene from a mixture. The method according to claim 1, wherein 100 to 5,000 ppm of N, N-diethylhydroxylamine is added to the total weight of cyclopentadiene and butadiene or the total weight of the mixture of cyclopentadiene and dicyclopentadiene and butadiene. Continuous process for preparing 5-vinyl-2-norbornene. 10 to 10,000 ppm 4-oxo-2,2,6,6-tetramethylpiperidine-1-oxyl relative to the total weight of cyclopentadiene and butadiene or the total weight of the mixture of cyclopentadiene and dicyclopentadiene and butadiene To the cyclopentadiene and butadiene by Diels-Alder reaction, characterized in that it is added continuously to the pressure resistant reactor of the resulting mixture, reacted in the pressure resistant reactor in the absence of the gaseous part and the reaction product is taken out continuously. A process for producing 5-vinyl-2-norbornene from or from a mixture of cyclopentadiene and dicyclopentadiene and butadiene. The method according to claim 3, wherein 100 to 5,000 ppm of 4-oxo-2,2,6,6-tetramethylpy is based on the total weight of cyclopentadiene and butadiene or the total weight of the mixture of cyclopentadiene and dicyclopentadiene and butadiene. A process for the continuous production of 5-vinyl-2-norbornene, characterized by the addition of ferridine-1-oxyl.